European Journal of Pharmaceutics and Biopharmaceutics xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
European Journal of Pharmaceutics and Biopharmaceutics journal homepage: www.elsevier.com/locate/ejpb
The effect of nanoparticle permeation on the bulk rheological properties of mucus from the small intestine M.D. Wilcox a,⇑, L.K. Van Rooij a, P.I. Chater a, I. Pereira de Sousa b, J.P. Pearson a a b
The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, UK Institute of Pharmacy, Department of Pharmaceutical Technology, University of Innsbruck, Innrain 80-82/IV, 6020 Innsbruck, Austria
a r t i c l e
i n f o
Article history: Received 17 September 2014 Revised 23 February 2015 Accepted in revised form 28 February 2015 Available online xxxx Keywords: Small intestinal mucus Nanoparticle Rheology Glycoprotein Bromelain
a b s t r a c t The effectiveness of delivering oral therapeutic peptides, proteins and nucleotides is often hindered by the protective mucus barrier that covers mucosal surfaces of the gastrointestinal (GI) tract. Encapsulation of active pharmaceutical ingredients (API) in nanocarriers is a potential strategy to protect the cargo but they still have to pass the mucus barrier. Decorating nanoparticles with proteolytic enzymes has been shown to increase the permeation through mucus. Here we investigate the effect of poly(acrylic acid) (PAA) nanoparticles decorated with bromelain (BRO), a proteolytic enzyme from pineapple stem, on the bulk rheology of mucus as well as non-decorated poly(lactic-co-glycolic acid) (PLGA) nanoparticles. Porcine intestinal mucus from the small intestine was incubated for 30 min in the presence of PLGA nanoparticles or polyacrylic nanoparticles decorated with bromelain (PAA-BRO). The effect of nanoparticles on the rheological properties, weight of gel, released glycoprotein content from mucus as well as the viscosity of liquid removed was assessed. Treatment with nanoparticles decreased mucus gel strength with PAA-BRO reducing it the most. PAA-BRO nanoparticles resulted in the release of increased glycoprotein from the gel network whereas mucus remained a gel and exhibited a similar breakdown stress to control mucus. Therefore it would be possible to use bromelain to increase the permeability of nanoparticles through mucus without destroying the gel and leaving the underlying mucosa unprotected. Ó 2015 Published by Elsevier B.V.
1. Introduction Mucus is a protective barrier that covers mucosal surfaces of the gastrointestinal (GI) tract [1,2]. Mucus can act as a lubricant for food bolus or chyme passing down the GI tract but also as a barrier against particulate matter such as pathogens [3]. This function of mucus also reduces the effectiveness of orally delivered therapeutic peptides [4], proteins [5] or nucleotides [6]. Therefore developing an effective vehicle to deliver active pharmaceutical ingredients (API) at effective concentrations across the mucus barrier is of great importance and interest [7]. There are several promising strategies for overcoming the barrier, such as self-nanoemulsifying drug delivery systems to pass through mucus [8], thiomers to attach to mucus for longer residency close to the mucosal surface [9], or decorating nanoparticles with mucolytic agents to aid their passage through mucus [10]. Several studies have already shown the ability to orally deliver, low amounts of either nanoparticles and their cargo or the cargo alone across mucus in the GI tract [10,11]. ⇑ Corresponding author. Tel.: +44 (0)191 208 5013; fax: +44 (0)191 208 7424. E-mail address: [email protected] (M.D. Wilcox).
By whichever means the API’s pass across the mucus, the barrier needs to remain intact so it can protect the underlying mucosa from the many potentially damaging agents contained within the lumen of the GI tract [12]. In this study we investigate the effects of two different nanoparticle systems, a poly(lactic-co-glycolic acid) (PLGA) nanoparticle and a poly(acrylic acid) (PAA) nanoparticle decorated with bromelain (BRO), on the bulk rheological properties of porcine intestinal mucus from the small intestine. 2. Materials and methods 2.1. Materials Porcine intestinal mucus was collected as follows and used throughout the experiments. Pig small intestines were obtained from a local abattoir immediately after slaughter and transported on ice to the laboratory. Sections of the intestines that did not visibly contain chyme were cut into 15 cm lengths and mucus was removed. To remove the mucus, gentle pressure was applied to one end of the section of small intestine with the fingers and
http://dx.doi.org/10.1016/j.ejpb.2015.02.029 0939-6411/Ó 2015 Published by Elsevier B.V.
Please cite this article in press as: M.D. Wilcox et al., The effect of nanoparticle permeation on the bulk rheological properties of mucus from the small intestine, Eur. J. Pharm. Biopharm. (2015), http://dx.doi.org/10.1016/j.ejpb.2015.02.029
2
M.D. Wilcox et al. / European Journal of Pharmaceutics and Biopharmaceutics xxx (2015) xxx–xxx
continuously applied unidirectionally to the opposite end. If the mucus contained debris it was cleaned as follows: the mucus was gently stirred (
Contents lists available at ScienceDirect
European Journal of Pharmaceutics and Biopharmaceutics journal homepage: www.elsevier.com/locate/ejpb
The effect of nanoparticle permeation on the bulk rheological properties of mucus from the small intestine M.D. Wilcox a,⇑, L.K. Van Rooij a, P.I. Chater a, I. Pereira de Sousa b, J.P. Pearson a a b
The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, UK Institute of Pharmacy, Department of Pharmaceutical Technology, University of Innsbruck, Innrain 80-82/IV, 6020 Innsbruck, Austria
a r t i c l e
i n f o
Article history: Received 17 September 2014 Revised 23 February 2015 Accepted in revised form 28 February 2015 Available online xxxx Keywords: Small intestinal mucus Nanoparticle Rheology Glycoprotein Bromelain
a b s t r a c t The effectiveness of delivering oral therapeutic peptides, proteins and nucleotides is often hindered by the protective mucus barrier that covers mucosal surfaces of the gastrointestinal (GI) tract. Encapsulation of active pharmaceutical ingredients (API) in nanocarriers is a potential strategy to protect the cargo but they still have to pass the mucus barrier. Decorating nanoparticles with proteolytic enzymes has been shown to increase the permeation through mucus. Here we investigate the effect of poly(acrylic acid) (PAA) nanoparticles decorated with bromelain (BRO), a proteolytic enzyme from pineapple stem, on the bulk rheology of mucus as well as non-decorated poly(lactic-co-glycolic acid) (PLGA) nanoparticles. Porcine intestinal mucus from the small intestine was incubated for 30 min in the presence of PLGA nanoparticles or polyacrylic nanoparticles decorated with bromelain (PAA-BRO). The effect of nanoparticles on the rheological properties, weight of gel, released glycoprotein content from mucus as well as the viscosity of liquid removed was assessed. Treatment with nanoparticles decreased mucus gel strength with PAA-BRO reducing it the most. PAA-BRO nanoparticles resulted in the release of increased glycoprotein from the gel network whereas mucus remained a gel and exhibited a similar breakdown stress to control mucus. Therefore it would be possible to use bromelain to increase the permeability of nanoparticles through mucus without destroying the gel and leaving the underlying mucosa unprotected. Ó 2015 Published by Elsevier B.V.
1. Introduction Mucus is a protective barrier that covers mucosal surfaces of the gastrointestinal (GI) tract [1,2]. Mucus can act as a lubricant for food bolus or chyme passing down the GI tract but also as a barrier against particulate matter such as pathogens [3]. This function of mucus also reduces the effectiveness of orally delivered therapeutic peptides [4], proteins [5] or nucleotides [6]. Therefore developing an effective vehicle to deliver active pharmaceutical ingredients (API) at effective concentrations across the mucus barrier is of great importance and interest [7]. There are several promising strategies for overcoming the barrier, such as self-nanoemulsifying drug delivery systems to pass through mucus [8], thiomers to attach to mucus for longer residency close to the mucosal surface [9], or decorating nanoparticles with mucolytic agents to aid their passage through mucus [10]. Several studies have already shown the ability to orally deliver, low amounts of either nanoparticles and their cargo or the cargo alone across mucus in the GI tract [10,11]. ⇑ Corresponding author. Tel.: +44 (0)191 208 5013; fax: +44 (0)191 208 7424. E-mail address: [email protected] (M.D. Wilcox).
By whichever means the API’s pass across the mucus, the barrier needs to remain intact so it can protect the underlying mucosa from the many potentially damaging agents contained within the lumen of the GI tract [12]. In this study we investigate the effects of two different nanoparticle systems, a poly(lactic-co-glycolic acid) (PLGA) nanoparticle and a poly(acrylic acid) (PAA) nanoparticle decorated with bromelain (BRO), on the bulk rheological properties of porcine intestinal mucus from the small intestine. 2. Materials and methods 2.1. Materials Porcine intestinal mucus was collected as follows and used throughout the experiments. Pig small intestines were obtained from a local abattoir immediately after slaughter and transported on ice to the laboratory. Sections of the intestines that did not visibly contain chyme were cut into 15 cm lengths and mucus was removed. To remove the mucus, gentle pressure was applied to one end of the section of small intestine with the fingers and
http://dx.doi.org/10.1016/j.ejpb.2015.02.029 0939-6411/Ó 2015 Published by Elsevier B.V.
Please cite this article in press as: M.D. Wilcox et al., The effect of nanoparticle permeation on the bulk rheological properties of mucus from the small intestine, Eur. J. Pharm. Biopharm. (2015), http://dx.doi.org/10.1016/j.ejpb.2015.02.029
2
M.D. Wilcox et al. / European Journal of Pharmaceutics and Biopharmaceutics xxx (2015) xxx–xxx
continuously applied unidirectionally to the opposite end. If the mucus contained debris it was cleaned as follows: the mucus was gently stirred (
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